Stabilizers for ships



March 24, 1959 1 KJEKSTAD 2,878,772

STABILIZERS FOR SHIPS Filed oct. e. 195'4 3 sheets-sheet 1 gm Q M* Gttorvncg March 24, J, KJEKSTAD. 2,878,772

STABILIZERS FOR SHIPS Filed Oct. 6, 1954 3 Sheets-Sheet 2 (ttorneg March 24, 1959 J, KJEKSTAD 2,878,772

STABILIZERS FOR SHIPS Filed Oct. 6. 1954 3 Sheets-Sheet 5 STABILIZERS FOR SHIPS Johannes Kjekstad, Royken, Norway Application October 6, 1954, Serial No. 460,549

\ z claims. (ci. 114-126) The invention relates to stabilizers of the fin type designed to counteract and at least partially neutralize the roll of ships. The use of activated fins for this purpose is well known, that is, fins which protrude laterally of the ship at or near the turn of the bilge and are mounted on stocks or shafts similar to rudder stocks so as to be angularly adjustable to vary the presentation angle. Such fins are usually of the retractable type, requiring considerable space inside the hull of the ship to house the fins and operating machinery. Such installations employ either a single fin or a plurality of fins on each side of the ship.

The single fin stabilizers are necessarily large to provide the required area for effective stabilization. Since the width of such fins of necessity is limited, their length is such as to cause them to extend a considerable distance beyond the hull lines of the ship when in operative position, with the result that they are subject to damage from foreign matters in the sea. Such damage may disable the fin so that it cannot be retracted, making it a menace to other vessels as Well as to its own ship.

Among the objects of the present invention are the confining of the fins within the normal limits of the bilge keels so as to avoid interference by or damage to the fins when the ship is moored alongside a pier or is in drydock; the positioning of the fins so as to combine maximum stabilizing effect with minimum danger of damage from any cause; the minimizing of the valuable space within the hull required for housing the operating mechanism of the stabilizing fins; the minimizing of turbulence from the fins either in neutral positions or when they are tilted out of their neutral positions; the standardizing of the ns in the interests of economy so that the same type of fins may be used with vessels of greatly varying size and speed; improvement in the effective area lof the fins while keeping their protrusion within normal limits of the bilge keels; the provision of stabilizing n units of standardized sizes and weights which may be manufactured economically by production methods and which may be installed in existing ships as well as in newly constructed ships and will be economical in their original installations and in replacement of damaged fins; and the guarding of the `tiltable fins from the encroachment of foreign bodies which may impair the movement of the fins.

The invention contemplates the use of relatively light weight small size stabilizing fins suitable for unit production and installation in sufficient numbers on a ship to give the necessary area for stabilization, each fin permissibly having its individual operating gear which may be automatically controlled by any suitable known servo mechanism operated, for exampleLby an electro hydraulic system responsive to a gyroscope, or from any suitable central control and operating unit located, for example, on the bridge or in the engine room of the ship.

More specifically the invention contemplates flattened areas on both sides at the turn of the bilge, each area i being of a size to accommodate one or more fins and the fins being mounted on oscillatable stems or shafts which extends through the attened area normal thereto and support the fins close to the outer surface of the flattened portion. The stems may bear within the bilge and will be operated by power means which may be and preferably is located within the bilge so as not to encroach substantially upon the space within the hull. The fin thus moves with the path of its inner face in a plane proximate and parallel to the flattened area and an arcuate guard is provided on the flattened area in front of the leading edge of the lin to exclude foreign matter, such as rope, steel wire, cable, chain, etc., from entering between the flat area and the fin and fouling the fin.

The invention includes other features of construction and has other objects and advantages as will/appear from the following description of embodiments of the invention shown in the accompanying drawings in which:

Fig. l is a side elevation of the hull of a ship equipped with stabilizing fins in embodiment of the invention;

Fig. 2 is a view similar to Fig. l but showing a different distribution of the stabilizing fins;

Fig. 3 is an enlarged cross sectional elevation taken on the plane of line 3 3 of Fig. 2;

Fig. 4 is an enlarged perspective of one of the stabilizing units of Fig. 2 as it is viewed from the horizontal;

Fig. 5 is a sectional oblique plan of the unit of Fig. 4 taken on the offset planes represented by the broken line 5 5 of Fig. 6 and viewed in the direction of the arrows;

Fig. 6 isa transverse vertical section taken on line 6 6 of Fig. 4;

Fig. 7 is a side elevation of the hull of a ship showing a modified form of bilge plating for the stabilizing unit;

Fig. 8 is an enlarged transverse sectional elevation on the line 8 8 of Fig. 7;

Fig. 9 is a view similar to Fig. 4 of a portion of the stabilizing assembly of Figs. 7 and 8; and

Fig. l0 is an venlarged perspective of a stabilizing assembly embodying a modified lin construction.

The number of stabilizing fins used on each side of a ship is determined by the characteristics of the ship, but for the purpose of illustration the number chosen is three. These may all be assembled on a common flat` tened area 10 at the turn of the bilge, as shown in Fig. l, or they may be spaced along the bilge, each on its own individual flattened area 11, as shown in Fig. 2. The fins 13 are mounted in immediate association with these flattened areas, as shown and as will be described.

The spaced stabilizing fin construction of Fig. 2 is selected for further detailed illustration and explanation. As shown in Fig. 3 the fins are disposed on each side of the hull, the opposing fins being oppositely tilted in known manner. In addition to the activated fins 13 the hull may be provided at the turn of the bilge with the usual bilge keel 14.

In the construction shown in Figs. l to 6, inclusive, the flattened areas 11 are formed by the use of flat bilge plates 11a which are disposed at an angle of substantially 45` to the horizontal and set within the otherwise rounded turn 15 of the bilge as a chord of the arc of the turn. The area between the break 16 from the rounded bilge plates at the curved portions 15 of the turn and the flat bilge plates ll at each end yof the flat bottom recess is occupied by rounded end plates 17. The flat bilge plates vand the round end plates *have marginal flanges overlapping and welded to the curved bilge plates.

The fins 13 are elongated streamlined hydrofoils -to minimize turbulence and drag on the ship, thevfins having each a fiat edge which is disposed adjacent and in cooperatve relation with the respective at bilge plate. They 'are-mounted 'on posts Aor stems '18 which pass through the at bilge plates 11a normal thereto and bear within the bilge where they are operatively connected to oscillatorypower means as will be described.

The fins Aare disposed with their long axes at right angles to their stems and with their'at edges close to their respective at plates 11a and means, comprising .an arcuate guard 19 concentric with the stem 18,'is

welded or otherwise secured to the at plate 11a in front of each tin to exclude foreign bodies from the space between the fin and its at plate.

The ship has the usual side frames 20 .and bottom bottom.

A water tight'compartrnent is formed for housing the motive mechanisms of the tins. In the case of the multiple unit arrangement of Fig. l this compartment ywill be of a size to house three motive mechanisms, while in the `single unit arrangement of Fig. 2 the` compartment will house a single motive mechanism.

As shown in Figs. 3, and 6, the water tight compartment has the flat bilge plate 11a for its outer wall, and the tank top 23 is joined to the side frames 20 and plate Z7 on each-side by an inner plate 25 which is parallel to bilge plate 11a. Theother two sides of the compartment are'formed by the side plate 27l and margin plate 28. The ends of the compartment are closed by bilge brackets 29 which are disposed at the same intervals as the oor or deep frames 21, the inner ones being provided with manholes 30 to atford access toall parts of the compartment. The inner plate 25 is also provided with a manhole having a removable cover 31.

The stem 18 has its bearings within this compartment. As shown it extends through a stufling box 32 on-the inner face of at bilge plate 11a into a thrust bearing 33 on the inner face of plate 25.

VThe power means for oscillating thestem 18 is a` suitable servo mechanism shown as `a reciprocating piston 34 in cylinder 35 which is mounted on a base on the flat bilge-plate 11a. The piston may be actuated vby air, steam or hydraulic fluid admitted through pressure lines 36. The tilting of the stabilizing fins may of course be effected by other servo, means such as an electric motor, and operated, for example, in response to gyroscopic means which function according to both the angle and speed of roll in known. manner.

The piston 34 is connected to the stem 18 through connecting rod-37 and crank arm 38 on the stem, the crank arm having a slotted opening 39 for the connecting wrist pin 40.

Thus movement of the piston 34 is transmitted to the stern 18, and tilts the lin 13 in the proper direction and the proper amount to counteract the roll and effectively stabilize the ship. In neutral position the tin is in line with the bilge keel but in an olf-neutral position pressure, depending upon the angle of the tin and the speed of the ship, is exerted onv the fin in the direction of approximately right angle to theV shaft or stem of the lin and concentric to the roll axis of the ship. Due to opposite setting of the ns on the two sides ofthe ship, they will 4produce opposing moments about the axis of roll and cooperate in their stabilizingveffect.

The width of the flattened areas is enough to contain ,the *arc of movement of the trailing end of the iin in its extreme position .in either direction from neutral. Therefore the n'never 4leaves lthe fiat surface and the yspace betweenl the tina and `bilge. plate `throughout the dlength of the n is constant in any positionofthetin.

-Nocspace is therefore openedup between thev neand `bilgein the angular settings ofthe iin tocause turbulence and -receive foreignibodies tofoul Vthe n, as would be CII the case if it moved with respect to a curved bilge plate.

'As'shown by the intersecting broken lines in Fig.`3 which form virtual continuation of the side and bottom shells, the tins 13 do not project beyond the normal limits of the bilge keels and therefore do not interfere with the berthing of the ship and there is no need to retract them. Moreover the eective area of the fins is increased, as compared to tins protruding-from curved bilge plates, by reason of the increase in `length represented by the radial length between the curved bilge plate at the turn 15 and the chord represented by the attened area. The recessed areas in which the tins are mounted create no appreciable turbulence.

However, instead of recessing theilattened areas, it may be desirable, especially in equipping existing ships with the stabilizing iins of the invention, to build up the rlat surface on the curved turn of the bilge, as by a tiat plate or bulb or blisteron the rounded bilge plates. Such la construction has theadvantage of `economy as welles ready availability for Vexisting ships.

Figs. 7, 8 and 9 show one way in which the atarea may ,be built up on the curved plates at the turn of the bilge. As shown, a plate having a flat portion 41 is secured at an angle of 45 on the curved bilge plates at the turn 15, being provided for this purpose with lat- `eral flange portions 42 which are welded to the side and .foreign bodies, for example, on to the fishing nets of fishing boats and trawlers on which the tin assemblies of the invention are used, it is contemplated that the leading edge of the tins may be rounded or charnfered as shown at y43 in Fig. l0, from their clearance of the lguards 19 to their outer faces, thereby streamlining the fins in their longitudinal as well as their transverse planes. This additional streamlining further reduces the turbulence caused by the tins.

Many boats such as fishing boats have a different cross sectional contour from that illustrated, being for example continuously curved from gunwale to keel without a distinct turn of the bilge from substantially flat sides to more or less flat bottoms. However it is obvious that the invention is equally applicable to such boats, the hulls having attened areas to provide locations for the tins, such areas being of a size to embrace the travel of the fins. The turn ofthe bilge when uscd herein is intended to contemplate such areas on such boats.

Fishing boats and many other boats are commonly of wood and do not have steel plates. It will be understood, therefore, that the use of the term plates herein is intended to comprehend any type of construction of hulls. Other modilications than those shown in thc ldrawings and above particularly described will readily occur to those skilled in the art within the principle and scope` of the invention as defined in the following claims.

What is claimed is:

l. In combination with the side and bottom frames of a ship, a stabilizer for the ship comprising, in combination, a bilge having double bottom plating comprising an outer bottom shell and a tank top, a hat bilge plate connecting the outer bottom shell to the side of the ship at the turn of the bilge, an inner plate spaced from and opposing the flat bilge plate connected to the tank top and to the side of the ship, a margin plate connect- ,ing the two said plates at theirsides opposite the side stem with its long axis 4at right angles to the stem and with its at edge cooperating with and adjacent the at plate, and power means within the compartment operatively connected to oscillate the stem.

2. In combination with the side and bottom frames of a ship, a stabilizer for the ship comprising, in combination, a bilge having double bottom plating and a water tight compartment at the turn of the bilge having a hat bilge plate at the turn of the bilge at an angle of substantially 45 to the side and bottom of the ship and an inner plate substantially parallel to the at bilge plate connected to the double bottom plating and to the side plating and having a longitudinal margin plate connected at its ends to bottom frames and at its upper side to the said inner plate and at its lower side to the at bilge plate, a n stem extending through the flat bilge plate normal thereto into the said compartment, bearings within the compartment for the stem, a iin attached to the stem 6 externally of and immediately adjacent the at bilge plate, and power means Within the compartment operatively connected to oscillate the stem.

References Cited in the file of this patent UNITED STATES PATENTS 650,758 Lake May 29, 1900 1,250,987 De Graw Dec. 25, 1917 1,533,328 Motora Apr. 14, 1925 2,190,617 Von Den Steinen Feb. 13, 1940 2,224,326 Wahl Dec. 10, 1940 2,346,337 Stub Apr. 11, 1944 2,550,752 Allan May 1, 1951 FOREIGN PATENTS 162,927 Great Britain May 12, 1921 690,383 Germany Mar. 28, 1940 

